Explore Everyday Health

Inside the Human Heart: 10 Fast (and Fun) Facts

There's more to the heart than what you may have learned in biology class. Here are some of our favorite lesser-known heart tidbits.

The all-important heart is constantly at work, pumping blood (about 2,000 gallons a day) filled with essential oxygen and nutrients to your body’s organs 24/7. Everything about the heart and how it works is interesting, but here are some nuggets of information we found particularly fascinating.

The Heart Sits in the Center of the Chest, Not On the Left Side

Does this blow your mind because you’ve always been told it’s on the left? When we place our hands over our hearts to pledge allegiance, we actually go a tad too far to the left. The heart is located in the middle of the chest, snuggled between the lungs.

A small percentage of people are born with dextrocardia, a condition in which the heart points more toward the right side of the chest than the left. According to the National Organization for Rare Disorders, people who have dextrocardia with situs inversus (when visceral organs like the liver and spleen are reversed too) can live normal lives without any disability.

In many cases, though, dextrocardia is associated with other heart defects or other misplaced, and even missing, organs that might require surgery to correct.

The Human Heart Beats Around 70 Times per Minute

This is a ballpark figure. According to Mayo Clinic, a healthy adult heart should beat anywhere from 60 to 100 times a minute while at rest. Do the math, and it adds up to around 100,000 beats a day and 2.5 billion beats in the average lifetime. That’s a lot of pumping.

Newborns have the fastest heartbeats, at 70 to 190 beats per minute, and the hearts of well-trained athletes tend to beat slower, at a rate of 40 to 60 beats per minute.

It’s important to watch your normal heart rate over time, too. A recent study published in the Journal of the American Medical Association found people whose resting heart rates increased from under 70 beats per minute to more than 85 beats per minute over 10 years had a 90 percent increased risk of dying from heart disease compared to those whose heart rates stayed around 70 beats per minute.

Having a Big Heart Isn't Necessarily a Good Thing

In the literal sense, an enlarged heart is a symptom of heart disease. For an adult, a normal heart is about the size of your fist.

An enlarged heart, termed cardiomegaly, can occur for a number of reasons, some temporary (stress on the body or pregnancy) and some tied to heart condition (weak heart muscle, coronary artery disease, heart valve problems, or abnormal heart rhythms).

Complications of cardiomegaly include cardiac arrest and sudden death (commonly seen in athletes), heart failure, heart murmurs, and blood clots, depending on the part of the heart enlarged.

And a Cold Heart Isn't Always a Bad Thing

Therapeutic hypothermia is actually a form of treatment for cardiac arrest. According to American Heart Association guidelines for inducing hypothermia, doctors cool a patient’s body to 91 degrees F, 7 degrees below average, in order to slow damage to brain and other organs that begin when the heart stops and restarts.

Research published in the Annals of Neurology in late 2010 found that two-thirds of patients who received the therapy after revival from cardiac arrest recovered and went home with good heart function.

Monday is the Most Common Day of the Week for Heart Attacks

Mondays get a bad rap — Manic Mondays, Monday blues, case of the Mondays — but where heart health is concerned, maybe it’s deserved. Research has shown that more heart attacks occur on Mondays than any other day of the week. One 2005 study published in the European Journal of Epidemiology found that the incidence of heart attack was 20 percent higher in men and 15 percent higher in women on Mondays.

Some experts theorize that the spike has to do with the stress of returning to work after a relaxing weekend, while others correlate Monday heart attacks with the effects of boozy Saturday nights.

Male-Pattern Baldness is a Sign of Heart Disease

This one may seem strange, but studies have shown that, compared to men with full heads of hair, men with crown hair loss have an increased risk of heart disease, about 23 percent higher, and complete hair loss on top of the head brings that number up to 36 percent. If you’re a guy who also has high blood pressure or high cholesterol, your risk is even higher.

Scientists can’t be sure what causes the link, but it might have something to do with testosterone. Too much of it interferes with hair growth on the head and also causes hardened arteries. The hair-loss link to heart disease could also be genetic.

The Body's System of Blood Vessels is More Than 60,000 Miles Long

There are three different kinds of blood vessels: Arteries carry blood from heart to organs, veins carry blood from organs and limbs back to the heart, and capillaries connect the two. Together, all of the arteries, veins, and capillaries in the body are long enough to go around the world more than twice.

How tall are you? Think about it.

Hardening of those arteries, called atherosclerosis, is the result of cholesterol and fat buildup in the vessels, which causes plaque. It can lead to coronary artery disease, heart attack, and stroke.

Women's Hearts Beat Faster Than Men's

A female human heart pumps about six beats faster per minute than a male heart, which can be explained by the gender difference in heart size. A male heart is bigger (by about 25 percent), so it can pump more blood in a single beat.

But having a quicker heart beat doesn’t equal quicker finishing times for runners. Because men’s hearts can pump more blood, on average, they tend to run faster than women.

Your Heart Doesn't Stop When You Sneeze

The increased pressure in your chest can affect blood flow to the heart, briefly changing its rhythm, but contrary to common belief, your heart doesn’t skip a beat when you sneeze. That doesn’t mean you should stop saying “bless you” or “gesundheit” after a sneeze, though. It’s only polite!

Despite the name, your heart doesn’t stop during heart failure either. It just can’t pump blood as well as it should. The only time the heart stops is during cardiac arrest.

The Aorta Is Nearly the Diameter of a Garden Hose

Sure it’s the largest artery in the body, running from the heart to the abdomen, but the thickness of a garden hose? That’s pretty big, and a weird thing to visualize.

But its size isn’t the only thing that makes the aorta a big deal: Most aneurysms, or bulges in the wall of an artery, will happen there.

Narrowing, or coarctation, of the aorta is a birth defect (doctors normally notice when a baby is a newborn) that can make it difficult for blood to pass through. Doctors have to perform surgery to remove the narrowed part or open it to correct the problem.